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Freescale 9S12 系列单片机应用笔记（SCI）3

时间：11-20 来源：互联网 点击：

  2. echaracterisavailable,thefunctionreturns
  3. *FALSE(0)otherwise,thefunctionreturnsTRUE(1).
  4. */
  5. unsignedcharSCIBufferIsEmpty(unsignedcharport);

  6. /**
  7. *ToseeifanymorecharacterscanbeplacedintheTxbuffer.
  8. *Inotherwords,thisfunctionchecktoseeiftheTxbufferisfull.
  9. *
  10. *@paramport,portcanbeSCI0/SCI1
  11. *@returnIfthebufferisfull,thefunctionreturnsTRUE
  12. *otherwise,thefunctionreturnsFALSE.
  13. */
  14. unsignedcharSCIBufferIsFull(unsignedcharport);

    #endif

  1. /**

  2. *SCI(SerialCommunicationInterface)BufferedSerialI/O
  3. *@filesci_ucos.c
  4. *@authorLiYuan
  5. *@platformmc9s12XX
  6. *@date2012-7-22
  7. *@version1.0.1
  8. */

  9. #include"derivative.h"/*derivative-specificdefinitions*/
  10. #include
  11. #include"includes.H"
  12. #include"sci.h"
  13. #include"sci_rtos.h"

    /**

  14. *GLOBALVARIABLES
  15. */
  16. SCI_RING_BUFSCI0Buf;
  17. SCI_RING_BUFSCI1Buf;

  18. /**
  19. *Toobtainacharacterfromthecommunicationschannel.
  20. *@paramport,portcanbeSCI0/SCI1
  21. *@paramto,istheamountoftime(inclockticks)thatthecallingfunctioniswillingto
  22. *waitforacharactertoarrive.Ifyouspecifyatimeoutof0,thefunctionwill
  23. *waitforeverforacharactertoarrive.
  24. *@paramerr,isapointertowhereanerrorcodewillbeplaced:
  25. **errissettoSCI_NO_ERRifacharacterhasbeenreceived
  26. **errissettoSCI_RX_TIMEOUTifatimeoutoccurred
  27. **errissettoSCI_BAD_CHifyouspecifyaninvalidchannelnumber
  28. *@returnThecharacterinthebuffer(orNULifatimeoutoccurred)
  29. */
  30. unsignedcharSCIGetCharB(unsignedcharport,unsignedshortto,INT8U*err)
  31. {
  32. #ifOS_CRITICAL_METHOD==3u/*AllocatestorageforCPUstatusregister*/
  33. OS_CPU_SRcpu_sr=0u;
  34. #endif
  35. unsignedcharc;
  36. unsignedcharoserr;
  37. SCI_RING_BUF*pbuf;

    switch(port)

  38. {/*Obtainpointertocommunicationschannel*/
  39. caseSCI0:
  40. pbuf=&SCI0Buf;
  41. break;

    caseSCI1:

  42. pbuf=&SCI1Buf;
  43. break;

    default:

  44. *err=SCI_BAD_CH;
  45. return(0);
  46. }
  47. OSSemPend(pbuf->RingBufRxSem,to,&oserr);/*Waitforcharactertoarrive*/
  49. if(oserr==OS_TIMEOUT)
  50. {/*Seeifcharactersreceivedwithintimeout*/
  51. *err=SCI_RX_TIMEOUT;/*No,returnerrorcode*/
  52. return(NUL);
  53. }
  54. else
  55. {
  56. OS_ENTER_CRITICAL();
  57. pbuf->RingBufRxCtr--;/*Yes,decrementcharactercount*/
  58. c=*pbuf->RingBufRxOutPtr++;/*Getcharacterfrombuffer*/
  59. if(pbuf->RingBufRxOutPtr==&pbuf->RingBufRx[SCI_RX_BUF_SIZE]){/*WrapOUTpointer*/
  60. pbuf->RingBufRxOutPtr=&pbuf->RingBufRx[0];
  61. }
  62. OS_EXIT_CRITICAL();
  63. *err=SCI_NO_ERR;
  64. return(c);
  65. }
  66. }

    /**

  67. *Thisfunctioniscalledbyyourapplicationtosendacharacteronthecommunications
  68. *channel.Thefunctionwillwaitforthebuffertoemptyoutifthebufferisfull.
  69. *Thefunctionreturnstoyourapplicationifthebufferdoesntemptywithinthespecified
  70. *timeout.Atimeoutvalueof0meansthatthecallingfunctionwillwaitforeverforthe
  71. *buffertoemptyout.ThecharactertosendisfirstinsertedintotheTxbufferandwill
  72. *besentbytheTxISR.Ifthisisthefirstcharacterplacedintothebuffer,theTxISR
  73. *willbeenabled.
  74. *
  75. *@paramport,portcanbeSCI0/SCI1
  76. *@paramcisthecharactertosend.
  77. *@paramtoisthetimeout(inclockticks)towaitincasethebufferisfull.Ifyou
  78. *specifyatimeoutof0,thefunctionwillwaitforeverforthebuffertoempty.
  79. *@returnSCI_NO_ERRifthecharacterwasplacedintheTxbuffer
  80. *SCI_TX_TIMEOUTifthebufferdidntemptywithinthespecifiedtimeoutperiod
  81. *SCI_BAD_CHifyouspecifyaninvalidchannelnumber
  82. */
  83. unsignedcharSCIPutCharB(unsignedcharport,unsignedcharc,unsignedshortto)
  84. {
  85. #ifOS_CRITICAL_METHOD==3u/*AllocatestorageforCPUstatusregister*/
  86. OS_CPU_SRcpu_sr=0u;
  87. #endif

    SCI_RING_BUF*pbuf;

  88. unsignedcharoserr;
  89. switch(port)
  90. {/*Obtainpointertocommunicationschannel*/
  91. caseSCI0:
  92. pbuf=&SCI0Buf;
  93. break;

    caseSCI1:

  94. pbuf=&SCI1Buf;
  95. break;

    default:

  96. return(SCI_BAD_CH);
  97. }

    OSSemPend(pbuf->RingBufTxSem,to,&oserr);/*WaitforspaceinTxbuffer*/

  98. if(oserr==OS_TIMEOUT)
  99. {
  100. return(SCI_TX_TIMEOUT);/*Timedout,returnerrorcode*/
  101. }
  102. OS_ENTER_CRITICAL();
  103. pbuf->RingBufTxCtr++;/*No,incrementcharactercount*/
  104. *pbuf->RingBufTxInPtr++=c;/*Putcharacterintobuffer*/
  105. if(pbuf->RingBufTxInPtr==&pbuf->RingBufTx[SCI_TX_BUF_SIZE])
  106. {
  107. pbuf->RingBufTxInPtr=&pbuf->pbuf->RingBufTxInPtr=&pbuf->RingBufTx[0];/*WrapINpo

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